Electrolytic separation of copper



Patented Aug. 4,1931

UNlTED STATES PATENT, \OFFICE max scnLo'rzrER, or BERLIN, GERMANY, AssIGnoR 'ro Asocmcron DE PnonUc'ronEs DE YODO 1m CHILE, ,o'F VALPARAISSO, CHILE ELECTROLYTIC SEPARATION OF COPPER No Drawing. Application filed September 28, 1929, Serial No. 396,003, and in Germany 0ctober29, 1928.

7 Since double, the "electrochemical equivalent of copper can be separated from solutions of cuprous salts compared with those of cupric salts, attempts have'been made to Obtain usable copper deposits for example from cuprous chloride (GuCl). Ithas been found however that cuprous chloride solution easily oxidizes in the presence of air and cupric chloride (CuCl is formed through which the quality of the copper of the liquid has been protected ,from the air by an air tight layer of paraffin or'the like. 'All these prior proposals for keeping away the ox 'gen of the air make the operations with t e electrolyte more difficult and in many cases'hind'er. the production of a uniformdeposit' The use of cuprous chloride solution therefore does not enable the desired technical result to be obtained.

It has now been found that solutions of cuprous iodide (CuI) are particularly suitable for. the separation of copper. Any cupric iodide (GU12) which may be formed, splits up into cuprous iodide and iodine which additively combines with the solvent;

' The electrolysis can be carried put without exclusion of air, so that all the above mentioned measures which render the operations diflicult are unnecessary.

Since cuprous iodide is not easily soluble in water, .it has been found advantageous to dissolve the cuprous iodide with the addition of such other saltsas increase its solubility.v It has been found that? cuprous iodide is so soluble when accompanied in particular by the halogenides of alkali. and alkaline earth, metals, chiefly the iodides, and also by sulphites, thiosulphates, cyan ides and the like,.tha t current densities of 400 amps/sqmeter and upwards can be amps/sq. meter are used.

used without the properties of the cathode copper being harmfully affected. In spite of the high content of alkali, or alkaline earth metal there is no liberation of hydrogen atgthe cathode. in spite of the low solubility .of cuprous iodide in Water, takes place steadily and quantitatively, and the cuprous content of the electrolyte remains constantf The proc- Solution of the anode,

ess takes place quantitatively at the anode above described process of copper By way of example a bath of the follow- 7 ing composition can be used in carrying out the process 1 60; gms. CuI.

,000 c. 0. water, 600 gms.KI, With this vbath a pressure about 0.3

..-fIt1has further been found that, colloids:

or capillary active substances can beadded to the cuprous iodide solution in order to volts .1 and a current density of about 400 obtain bright and smooth. coatings, withv30 out the metal becoming brittlefas occurs for example with the addition of these substances to copper sulphate solution. Among colloids, glue, gelatine and the like and among capillary active substances, phenols, s5

1.-A method of separating'copper which consists in electrolyzing.an aqueous solution containing cuprous iodide. x 2. A method of separating copper which consists in" electrolyzingan aqueous solution containing cuprous iodide without excluding air from contact with the solution.

3. A method of depositing copper which consists in elect-rolyzing an aqueous solution contalning cuprous iodide in contact with the atmosphere 4;. A method of separating copper which consists in electrolyzing an aqueous solution containing cuprous iodide and a salt of an alkali or alkaline earth metal.

5. A. method of separating copper which consists in electrolyzingan aqueous solution containing cuprous iodide and a halogenide of an alkali or alkaline earth metal.

6. A. method of separating copper which consists in electrolyzing an aqueous solution containing cuprous iodide and an iodide of an alkali or alkaline earth metal 7. A method of separating copper which consists in electrolyzing an aqueous solution containing cuprous iodide and potassium iodide. v

8. A method of separating copper which consists in electrolyzing a solution contain ing cuprous iodide and potassium iodide without excluding air.

9. A method of separating copper which consists in electrolyzing a solution containing cuprous iodide and potassium iodide witha copper anode, without excluding air.

10. An electrolyte for the electrolytic separation of copper comprising an aqueous solution containing cuprous iodide.

11. An electrolyte for the electrolytic separation of copper comprising an aqueous solution containing cuprous iodide and an alkaline iodide.

In testimony whereof I have signed my name to this specification.

MAX SCHLOTTER.

aerate? 

